1 files changed, 176 insertions, 0 deletions
diff --git a/gcc/rust/rust-object-export.cc b/gcc/rust/rust-object-export.cc
new file mode 100644
index 0000000..e1c0a92
--- /dev/null
+++ b/gcc/rust/rust-object-export.cc
@@ -0,0 +1,176 @@
+/* rust-backend.c -- Rust frontend interface to gcc backend.
+   Copyright (C) 2010-2022 Free Software Foundation, Inc.
+
+   This file is part of GCC.
+
+   GCC is free software; you can redistribute it and/or modify it under
+   the terms of the GNU General Public License as published by the Free
+   Software Foundation; either version 3, or (at your option) any later
+   version.
+
+   GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+   WARRANTY; without even the implied warranty of MERCHANTABILITY or
+   FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+   for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with GCC; see the file COPYING3.  If not see
+   <http://www.gnu.org/licenses/>.  */
+
+#include "rust-system.h"
+#include "coretypes.h"
+#include "target.h"
+#include "tree.h"
+#include "memmodel.h"
+#include "tm_p.h"
+#include "diagnostic.h"
+#include "simple-object.h"
+#include "stor-layout.h"
+#include "intl.h"
+#include "output.h" /* for assemble_string */
+#include "common/common-target.h"
+
+// satisfy intellisense
+#include "options.h"
+
+/* The segment name we pass to simple_object_start_read to find Rust
+   export data.  */
+
+#ifndef RUST_EXPORT_SEGMENT_NAME
+#define RUST_EXPORT_SEGMENT_NAME "__GNU_RUST"
+#endif
+
+/* The section name we use when reading and writing export data.  */
+
+#ifndef RUST_EXPORT_SECTION_NAME
+#define RUST_EXPORT_SECTION_NAME ".rust_export"
+#endif
+
+#ifndef TARGET_AIX
+#define TARGET_AIX 0
+#endif
+
+/* Return whether or not GCC has reported any errors.  */
+
+bool
+saw_errors (void)
+{
+  return errorcount != 0 || sorrycount != 0;
+}
+
+/* Return the alignment in bytes of a struct field of type T.  */
+
+unsigned int
+rust_field_alignment (tree t)
+{
+  unsigned int v;
+
+  v = TYPE_ALIGN (t);
+
+#ifdef BIGGEST_FIELD_ALIGNMENT
+  if (v > BIGGEST_FIELD_ALIGNMENT)
+    v = BIGGEST_FIELD_ALIGNMENT;
+#endif
+
+#ifdef ADJUST_FIELD_ALIGN
+  v = ADJUST_FIELD_ALIGN (NULL_TREE, t, v);
+#endif
+
+  return v / BITS_PER_UNIT;
+}
+
+/* This is called by the Rust frontend proper to add data to the
+   section containing Rust export data.  */
+
+void
+rust_write_export_data (const char *bytes, unsigned int size)
+{
+  static section *sec;
+
+  if (sec == NULL)
+    {
+      gcc_assert (targetm_common.have_named_sections);
+      sec = get_section (RUST_EXPORT_SECTION_NAME,
+			 TARGET_AIX ? SECTION_EXCLUDE : SECTION_DEBUG, NULL);
+    }
+
+  switch_to_section (sec);
+  assemble_string (bytes, size);
+}
+
+/* The rust_read_export_data function is called by the Rust frontend
+   proper to read Rust export data from an object file.  FD is a file
+   descriptor open for reading.  OFFSET is the offset within the file
+   where the object file starts; this will be 0 except when reading an
+   archive.  On success this returns NULL and sets *PBUF to a buffer
+   allocated using malloc, of size *PLEN, holding the export data.  If
+   the data is not found, this returns NULL and sets *PBUF to NULL and
+   *PLEN to 0.  If some error occurs, this returns an error message
+   and sets *PERR to an errno value or 0 if there is no relevant
+   errno.  */
+
+const char *
+rust_read_export_data (int fd, off_t offset, char **pbuf, size_t *plen,
+		       int *perr)
+{
+  simple_object_read *sobj;
+  const char *errmsg;
+  off_t sec_offset;
+  off_t sec_length;
+  int found;
+  char *buf;
+  ssize_t c;
+
+  *pbuf = NULL;
+  *plen = 0;
+
+  sobj = simple_object_start_read (fd, offset, RUST_EXPORT_SEGMENT_NAME,
+				   &errmsg, perr);
+  if (sobj == NULL)
+    {
+      /* If we get an error here, just pretend that we didn't find any
+	 export data.  This is the right thing to do if the error is
+	 that the file was not recognized as an object file.  This
+	 will ignore file I/O errors, but it's not too big a deal
+	 because we will wind up giving some other error later.  */
+      return NULL;
+    }
+
+  found = simple_object_find_section (sobj, RUST_EXPORT_SECTION_NAME,
+				      &sec_offset, &sec_length, &errmsg, perr);
+  simple_object_release_read (sobj);
+  if (!found)
+    return errmsg;
+
+  if (lseek (fd, offset + sec_offset, SEEK_SET) < 0)
+    {
+      *perr = errno;
+      return _ ("lseek failed while reading export data");
+    }
+
+  buf = XNEWVEC (char, sec_length);
+  if (buf == NULL)
+    {
+      *perr = errno;
+      return _ ("memory allocation failed while reading export data");
+    }
+
+  c = read (fd, buf, sec_length);
+  if (c < 0)
+    {
+      *perr = errno;
+      free (buf);
+      return _ ("read failed while reading export data");
+    }
+
+  if (c < sec_length)
+    {
+      free (buf);
+      return _ ("short read while reading export data");
+    }
+
+  *pbuf = buf;
+  *plen = sec_length;
+
+  return NULL;
+}